import java.util.Scanner;

public class Solution {

    public static String func(String str){
        boolean[] flags = new boolean[127];
        StringBuilder stringBuilder = new StringBuilder();
        for (int i = 0; i < str.length(); i++) {
            char ch = str.charAt(i);
            if (!flags[ch]){
                stringBuilder.append(ch);
                flags[ch] = true;
            }
        }
        return stringBuilder.toString();
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        while (in.hasNextLine()){
            String str = in.nextLine();
            String ret = func(str);
            System.out.println(ret);

        }
    }
}
